#!/usr/bin/ruby

# convert existing files on an ext4 filesystem to use extents
# after an upgrade from ext3
# can be run on a live mounted rw filesystem (use at your own risks)

# (c) Y. Guillot 2010
# redistribute under the WtfPLv2

EXT4_IOC_MIGRATE = (?f.ord << 8) | 9

$count = 0
$t = Time.now
def migrate(f)
	if Time.now > $t+0.4
		$stderr.print(' '*80+"\r"+f+"\r")
		$t = Time.now
	end
	case File.ftype(f)
	when 'directory'
		Dir.entries(f).each { |e|
			next if e == '.' or e == '..'
			migrate(File.join(f, e))
		}
	when 'file'
		File.open(f) { |fd|
			fd.ioctl(EXT4_IOC_MIGRATE, 0)
		}
		$count += 1
	end
rescue Errno::EINVAL	# may already use extents
rescue
	puts "failed to migrate #{f.inspect}: #$!"
end

ARGV.each { |f| migrate f }

puts ' '*80+"\r"+"converted #$count files"